Fencing support base



FIG. 1 is a top side perspective view of a fencing support base;

FIG. 2 is a top elevational view thereof;

FIG. 3 is a bottom elevational view thereof;

FIG. 4 is a front side elevational view thereof;

FIG. 5 is a back side elevational view thereof;

FIG. 6 is a left side elevational view thereof; and,

FIG. 7 is a right side view thereof.

The broken line areas show portions of the fencing support base that form no part of the claimed design. 

CLAIM The ornamental design for a fencing support base, as shown and described. 